No abstract

Laser speckle imaging (LSI) as a label-free flow mapping technique has numerous potential clinical applications and plays an increasingly important role in translational medicine. Conventional LSI, however, is limited to qualitative flow change assessment and two-dimensional topographic imaging. Here we report a light-sheet laser speckle imaging (LSH-LSI) platform. This new technique takes advantage of the optical sectioning capability inherent in selected plane illumination to achieve tomographic imaging of vascular structures and blood flow velocity with high spatiotemporal resolution. We conducted on this novel platform zebrafish imaging experiments to reveal complicated laser speckle dynamic characteristics, for which revised theoretical models were necessary for quantitatively retrieving the flow velocity. Furthermore, LSH-LSI could generate vector velocity maps based on additional processing of scalar laser speckle velocimetry results acquired at high frame rates.

We have developed a laser speckle imaging method based on selected plane illumination. Optical sectioning is achieved for 3D quantitative flow imaging.

Structured illumination microscopy (SIM) is an established optical superresolution imaging technique. However, conventional SIM based on wide-field image acquisition is generally limited to visualizing thin cellular samples. We propose combining one-dimensional image rescan and structured illumination in the orthogonal direction to achieve superresolution without the need to rotate the illumination pattern. The image acquisition speed is consequently improved threefold, which is also beneficial for minimizing photobleaching and phototoxicity. Optical sectioning in thick biological tissue is enhanced by including a confocal slit in the system to significantly suppress the out-of-focus background and the associated noise. With all the technical improvements, our method captures threedimensional superresolved image stacks of neuronal structures in mouse brain tissue samples for a depth range of more than 200 μm.